"I promised the actors that no matter what, we would have time to discuss every single line," Weitz explains. "There was a line that he felt was repetitive and Rob wasn't feeling where he was in the scene. We worked it out and came up with some alternate dialogue. I can work on the fly a bit because I'm a writer-director, which is helpful. I don't feel stuck or panicky when an actor is not down with a particular piece of dialogue."

After this film, Weitz will depart the "Twilight" saga; director David Slade -- known for his edgy-with-a-capital-"E" feature debut "Hard Candy" and the bloody horror outing, "30 Days of Night" -- will helm the third film in the franchise, "The Twilight Saga: Eclipse," which goes before cameras Aug. 17 and is set for release next summer on June 30.

Producer Wyck Godfrey says changing directors while maintaining the same actors and screenwriter Melissa Rosenberg will bring a different energy to each "Twilight" movie without disrupting the overall continuity. Weitz was brought on after Hardwicke opted out of doing "New Moon," citing scheduling conflicts, but Slade's selection raised some eyebrows. The heart of the story is the romance between Edward and Bella after all, and Slade doesn't seem like much of a romantic.

Godfrey points out that "Eclipse" is darker in tone than the stories that precede it and more action-packed, making Slade the right choice.

"Ever since I saw 'Hard Candy,' I was obsessed with him as a filmmaker," the producer says. "That's a female point-of-view movie, and it's very different than the average female point-of-view movie. He's also done tons of videos that are female friendly, and he has some teeth to him too, which I think is good."

A bigger question mark hangs over what is the most adult entry in Meyer's series, "Breaking Dawn." Godfrey was mum as to specifics, saying only that everyone involved fully intends to make what would be the fourth movie. (The website IMDb.com lists "Breaking Dawn" as in development with a tentative 2011 release date.)

"We're shooting 'New Moon,' prepping 'Eclipse,' doing all the marketing -- it's a little overwhelming to really think in a detailed manner of how we're going to crack this, but we have every intention to," he said of "Dawn."

Much at stake

It's now July, and Weitz will face 6,000-plus screaming fans as he unveils never-before-seen footage from "New Moon" at Comic-Con International in San Diego on Thursday. At last year's convention, months before "Twilight" was released, the delighted squeals were nearly deafening.

Driving home from a day of post-production, Weitz says he understands what's at stake. There are 450 visual effects shots to complete, in addition to the score and the movie's soundtrack, which he says will feature songs from Radiohead, Muse and Band of Skulls, among others. But the sequences he's readying for the event -- one, an action scene that will feature some of those effects, the other, a love scene sure to elicit hysteria from the crowd -- will be done in time.

With so much on the line at Comic-Con, where word of mouth can often make or break a project, Weitz is feeling fairly confident that the reaction will be positive, especially since many of the cast members will be there.

"It's a rare and wonderful feeling to know that people are going to want to see what you're making," he says. "The fear sometimes when you're making a film is that you've gotten everybody all dressed up with nowhere to go. Certainly, there is the possibility that I can drop the ball . . . . But at least people are going to go and see it."

gina.mcintyre@latimes.com